[MrFixr55]

Does the Philco pot have only 1 element (2 or 3 terminals) or is it ganged (5 or 6 terminals)?

You state that one connection is to B-. Is it to chassis ground? is it one end or is it the wiper?

The early 27 uses a 1KOhm pot and controls only the cathode bias of the 2 24s. the wiper goes to the cathode and the entire resistor is in series with the speaker filed coil across B+
The late 27 and the 26 use an 8K pot whose center tap is grounded. one leg is tied to the cathodes of the two 24s; the other leg is tied to the antenna connection.

The Philco 91 uses a pot in the audio input like most radios of the later 30s to the end of the tube era.

As to what wattage pot is needed, my rough guess is that the pot must dissipate 5W at minimum volume. This is assuming that at minimum volume, the voltage across the pot is 50V. I may be totally wrong on this; the voltage may be much less. However, the maximum plate and screen current at 180V for this tube is approximately 5 mA. for 2, this is 10 mA. At 50V, 50V X10mA = 5W. So I would use a pot with a minimum of 5W dissipation. A 10K pot would work. I don't know if you can find one of these with 5W dissipation; that value is rather high for a 10K pot. I don't have a Gloritone. The one I fixed was for a friend who sold it. Maybe one of the members who has a working one can measure cathode bias voltage to ground at minimum volume. My guess is that whatever wattage, a linear taper pot can be used. If the pot is a 2K pot, it should be wired per the early schematic. If the Pot is 5K or higher, the later scheme can be used.

In any case, when using this or any radio where the volume is controlled by varying cathode bias, start with the volume control at minimum. Since there is no AVC, a high volume setting will cause the RF stages will saturate with a strong station, causing no sound. this is not a defect; this is how the radio operates.

BTW, the cathode bias resistor for the detector is marked 50 M. This is not megohms; the "M" indicated kilohms.